Nano-Diamond Coated Cutting Tools: Modeling Tool Geometry Effects

本研究的目的是通过对刀具几何效应的基础研究，更新纳米结构金刚石(纳米金刚石)涂层刀具的设计。超硬、附着力好、光滑的纳米金刚石涂层有可能使涂层工具技术发生革命性变化，以满足现代加工的挑战。然而，由于金刚石沉积和切割过程的交织影响，刀具几何形状如何影响金刚石涂层刀具在机械加工中的性能却知之甚少。研究方法包括使用纳米压痕对沉积残余应力进行实验研究和计算建模，使用整体压痕方法研究涂层与基材的结合，使用二维正交法加工具有涂层属性的金刚石涂层刀具的切削应力和温度，以及使用三维加工方法对涂层刀具失效进行研究。研究对象将围绕不同的刀具几何形状进行综合研究，包括刀具的微观和宏观特征，如刀具的刃口半径和刀尖角度。刀具几何形状、涂层分层和刀具寿命之间的关系，以及涂层刀具从沉积到加工的热机械演化过程，将指导纳米金刚石涂层刀具的优化设计。这项研究将直接造福于社会，因为刀具技术的进步将增强民族制造商在全球竞争中的实力。这项研究与一家刀具制造商、一家金刚石镀膜机和汽车行业的刀具用户合作，为针对特定加工任务量身定做的纳米金刚石涂层刀具的高效设计提供了渠道。此外，对金刚石涂层刀具加工行为的新认识将转化为制造业迫切需要的纳米金刚石涂层钻头和其他复杂形状刀具的开发。这项研究的进一步社会影响包括由代表性不足的学生进行的本科生研究，他们还将协调广泛的研究传播。此外，这项研究将通过两年制机床技术专业的学生参与项目来接触到社区。

The objective of this research is to renovate the designs of nanostructured diamond (nano-diamond) coated cutting tools through fundamental studies of tool geometry effects. Ultrahard, well-adherent and smooth nano-diamond coatings have a potential to revolutionize the coated tooling technology to meet modern machining challenges. How the tool geometry affects diamond coated tool performance in machining, however, is least understood because of the interwoven effects of both the diamond deposition and cutting processes. The research approach includes experimental investigations and computational modeling of deposition residual stresses using nanoindentation, coating-substrate adhesion using bulk indentation, cutting stresses and temperatures of diamond coated tools inherited with coating attributes using two-dimensional orthogonal machining, and coating tool failures using three-dimensional machining. The subjects will be integratively studied centered on variable tool geometry including micro- and macro-features such as the cutting edge radius and nose angle. The connections between the tool geometry, coating delamination and tool life, correlated with the thermomechanical evolution of the coated tools from deposition to machining, will guide optimal designs of nano-diamond coated tools.This research will directly benefit society by advancement of cutting tool technology that will strengthen the national manufacturers in global competition. Collaborated with a tool maker, a diamond coater, and tool users from automotive industry, this research offers channels for efficient designs of nano-diamond coated tools tailored to specific machining tasks. In addition, the new knowledge of diamond coating tool behavior in machining will be transformed into development of nano-diamond coated drills and other complex-shape tooling, which are critically needed in the manufacturing industry. Further societal impacts of this research include undergraduate research by underrepresented-group students, who will also coordinate broad research dissemination. In addition, this research will reach out to the community through project participation by machine tool technology students from two-year college programs.